JP3638861B2 - Booster unit - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a booster unit, and more particularly, to a DC power generated by an independent DC power source such as a solar cell, applied to a general AC load for home use or office use or an inverter device for supplying power to an existing commercial power system. More particularly, the present invention relates to a function of connecting the DC power source to the boosting unit and the inverter device.
[0002]
[Prior art]
A solar battery that is a direct current power source outputs direct current power when the solar radiation is strong. It is known as a simple and clean energy source because it can output direct-current power with only a solar cell without any other energy source such as a secondary battery and does not discharge harmful substances.
[0003]
The DC power generated by the solar cell is converted into AC power in the inverter device, and the power is supplied to a general AC load or an existing commercial power system. In the inverter device, a plurality of solar cell strings are connected via a connection box that is an external device having a connection function.
[0004]
By the way, when installing a solar cell on the roof of a house, the shape of the surface of the roof on which the solar cell is placed does not necessarily match a standard combination of rectangular solar cell dimensions, and the standard dimensions at both ends of the roof. There are cases where it must be less than the combination. For this reason, the solar cell string includes, for example, a standard string of 8 or 9 solar cell modules connected in series to each other and a standard string of solar cells in series for placement at both ends of the roof. A non-standard string of less than a few solar cell modules is provided. A booster unit is connected to the non-standard string for boosting to a DC voltage similar to that of a standard solar cell string. Hereinafter, a conventional example of a photovoltaic power generation system including these boosting unit, junction box, and inverter device will be described with reference to FIG.
[0005]
In FIG. 8, only two solar cell strings are shown for simplification of the drawing, but it goes without saying that more solar cell strings are usually included.
[0006]
The output power of the standard solar cell string 102 a is directly connected to the connection box 103. The connection box 103 is provided for connecting the standard solar cell string 102 a and the inverter 104. On the other hand, the output power of the nonstandard solar cell string 102 b is connected to the junction box 103 via the booster unit 101. Boost unit 101 includes a reactor 106, a switching element 107, a diode 108, a capacitor 109, and a control circuit 110 in order from the input side. The junction box 103 is provided with backflow prevention diodes 111a and 111b for each of the solar cell strings 102a and 102b so that power does not flow backward from the inverter 104 side to the solar cell strings 102a and 102b. A lightning surge absorber 112 is provided to prevent a lightning surge from intruding on the side of 104. Further, an input breaker 113 is provided for connecting or disconnecting the solar cell strings 102a, 102b and the inverter 104 side.
[0007]
The inverter 104 converts the DC power output from the connection box 103 into AC power having the same phase and frequency 50/60 Hz as the commercial power system 105 and supplies the AC power to the commercial power system 105.
[0008]
FIG. 9 is a specific block diagram of the control circuit 110 shown in FIG. In FIG. 9, the control circuit 110 includes a step-up ratio setting unit 114, a signal setting calculation unit 115, a triangular wave generation unit 116, a signal comparison unit 117, and a gate drive unit 118. The step-up ratio setting unit 114 sets the ratio between the number n1 of solar cell modules included in the standard solar cell string 102a and the number n2 of solar cell modules included in the non-standard solar cell string 102b, that is, the step-up ratio α (= n1 / n2). Set. The set boost ratio α is given to the signal setting calculation unit 115.
[0009]
As shown in FIG. 10, the signal setting calculation unit 115 calculates the signal set value M based on the boost ratio α set by the boost ratio setting unit 114 and supplies the calculated signal set value M to the comparison input terminal of the signal comparison unit 117. A triangular wave T having an amplitude value from 0 to 1 generated by the triangular wave generator 116 is applied to the reference input terminal of the signal comparator 117. The signal comparison unit 117 compares the signal set value M with the triangular wave T, and performs PWM (pulse width modulation) control for outputting a gate OFF level when the signal set value M is larger than the triangular wave T. As a result, the pulse signal PS shown in FIG. 10 is output from the signal comparison unit 117 and supplied to the gate drive circuit 118. The gate drive circuit 118 drives the switching element 107 shown in FIG.
[0010]
As described above, the boost unit 101 performs PWM control based on a preset boost ratio α to perform constant boost ratio control for switching the switching element 107 on and off, and boosts input power from the solar cell string 102b side. To do.
[0011]
[Problems to be solved by the invention]
However, regarding the connection of the solar cell 102b string, the boost unit 101, the junction box 103 and the inverter 107 shown in FIG. 8, the wiring from the non-standard solar cell string 102b installed on the roof of the building is connected to the boost unit 101. Then, it is wired to the inverter 104 via the connection box 103 which is an external device having a connection function. For this reason, in the conventional method, the installation space for the booster unit 101 and the connection box 103 must be provided exclusively inside and outside the building.
[0012]
Further, a casing and wiring materials dedicated to the boosting unit 101 and the connection box 103 are required, which may lead to an increase in the cost of the entire apparatus. Moreover, since the wiring for connecting from the booster unit 101 to the junction box 103 is provided indoors and outdoors, there is a risk that the scenery indoors and outdoors may be damaged.
[0013]
Further, when the boosting unit 101 is operating with constant boost ratio control during the daytime when solar radiation is strong, the boost ratio cannot be changed when the output voltage rises above the input voltage range of the inverter 104. Further, an overvoltage is applied to the inverter 104, which may cause a failure.
[0014]
Further, if an appropriate boost ratio α is not set by the boost ratio setting unit 114 in the control circuit 110 of the boost unit 101, for example, if a larger boost ratio α than the actual one is set incorrectly, the output voltage of the inverter 104 If the voltage exceeds the input voltage range, an overvoltage may be applied to the inverter 104, leading to failure.
[0015]
Further, when the boosting unit 101 is operating during the daytime when the solar radiation is strong, if the switching element 107 in the boosting unit 101 is short-circuited and the short-circuit current continues to flow, the switching element 107 is heated, There was a risk that the booster unit 101 would fail.
[0016]
Therefore, the main object of the present invention is to provide a boosting unit that reduces the dedicated installation space inside and outside the building with respect to the connection between the solar cell, the boosting unit, the junction box, and the inverter device.
[0017]
Another invention is a boost unit that integrates a dedicated housing to reduce the cost of the entire device and eliminates the wiring for connecting the boost unit to the junction box so as not to damage the indoor / outdoor landscape. Is to provide.
[0018]
Another object of the present invention is to provide a safe boosting unit that does not continue to generate a short-circuit current even if an overvoltage is not applied to the inverter device during operation of the boosting unit, and further, even if the switching element is faulty short-circuited.
[0019]
[Means for Solving the Problems]
  The present invention is a boosting unit that boosts and converts a voltage of a DC power source such as a solar cell by an opening and closing operation of a switching circuit, and supplies the boosted DC voltage to AC power. Boosting means for boosting, and input connection function part for directly connecting DC power supply and boosting meansThe boosting means performs constant boost ratio control that keeps the boost ratio constant when the output voltage of the boost unit is lower than the set voltage, and outputs the boost unit when the output voltage of the boost unit is higher than the set voltage. Constant voltage control is performed by changing the step-up ratio so that the voltage is a constant voltage lower than the set voltage.It is characterized by that. Thereby, regarding the connection between the solar cell, the boosting means, and the inverter device, it is possible to reduce a dedicated space for installation inside and outside the building. Moreover, since the wiring for connecting from the booster unit to the junction box can be omitted, the indoor landscape is not impaired.
  In addition, when the output voltage of the booster unit is lower than the set voltage, the booster ratio is controlled so that it is a nonstandard solar cell string when the booster is operating during the daytime when the solar radiation is strong. However, DC power similar to that of a standard solar cell string can be supplied to the inverter device. Therefore, it is possible to effectively use a limited space such as a roof of a building.
  Further, when the output voltage of the boost unit is higher than the set voltage, constant voltage control is performed by changing the boost ratio, so that the output voltage can be prevented from exceeding the set value. Therefore, overvoltage can be applied to the inverter device and failure can be prevented, and safety can be improved.
[0020]
  Further, the input connection function unit includes backflow prevention means for preventing current from flowing back from the boosting means side to the DC power supply side.,straightAnd a lightning surge prevention means for preventing a lightning surge from entering the boosting means side from the flow power supply. As a result, current does not flow backward from the boosting means and the inverter device side to the solar cell side, and the solar cell side, the boosting means side, the boosting means side, and the inverter device side can be safely connected or disconnected during construction or the like. can do.Further, it is possible to prevent lightning surges from entering the boosting means side and the inverter device side from the solar cell side during a lightning strike, thereby ensuring the safety of the inverter device.
[0025]
  In addition, input connectionFunctional partIsOf the boost unitTrip signal generating means for generating a trip signal in response to the output voltage becoming overvoltage;Input connection disconnection to connect DC power supply and boosting means, and to disconnect DC power supply and boosting means in response to trip signalMeans. As a result, when the booster is operating during the daytime when the solar radiation is strong, and when the boost voltage constant control or constant voltage control is being performed, it is detected that the output voltage has become overvoltage. Since the column means performs a trip operation to open the circuit, it is possible to prevent overvoltage from being applied to the inverter device and causing a failure, thereby improving safety.
[0026]
The output voltage is detected by trip signal generating means. As a result, when the boosting means is operating during the daytime when the solar radiation is strong, the output voltage monitoring for determining the overvoltage abnormal state can be performed by determining the overvoltage abnormal state, and the trip signal generating means Since the trip signal is generated and the circuit is opened by the opening means, it is possible to prevent the overvoltage from being applied to the inverter device and causing a failure, so that safety can be improved.
[0027]
  Further, the trip signal generating means generates a trip signal in response to a short circuit failure in the boosting means.ProduceIt is characterized by that. As a result, when the boosting means is operating, even if the boosting means is short-circuited and a short-circuit current flows between the solar cell and the boosting means,Input connection disconnectionSince the means trips and the circuit is opened, it is possible to prevent the short-circuit current from continuously flowing, to prevent the boosting means from being heated by the short-circuit current and to prevent the boosting unit from failing, and to improve safety.
[0028]
  In addition, the trip signal generatorStageTo increase the temperature of the boosterBased on this, it is detected that a short-circuit fault has occurred in the boosterIt is characterized by doing. As a result, when the boosting unit is operating, if the boosting unit fails and short-circuits and a short-circuit current flows between the solar cell and the boosting unit, the boosting unit heats up and the temperature rises. Since the input disconnection connection means trips due to an abnormal temperature rise and opens the circuit, the short-circuit current is prevented from continuing to flow, the short-circuit current heats the boosting means, and the boosting unit fails. Can be prevented and safety can be improved.
[0029]
  In addition, the trip signal generatorStageThe output voltage of the boost unit isOf inverter equipmentIn response to exceeding the predetermined input voltage rangeGenerate trip signalTo do. ThisInverter deviceFailure due to overvoltage can be prevented.
[0032]
In addition, it includes a housing for storing the input connection function unit and installing it outdoors. The housing discharges rainwater led to the lower part of the drainage channel that guides the rainwater to the lower part when it rains. And a discharge port. Thereby, it can prevent that rainwater splashes on the electroconductive part of the circuit accommodated in the housing | casing.
[0033]
  In addition, the outside of the housing is boostedunitA heat dissipating means for radiating heat generated from the outside to the outside is provided. Thereby, the heat dissipation effect can be enhanced.
[0034]
Furthermore, it includes a metal plate for covering the heat dissipation means of the housing and supporting the housing on the wall surface. Thus, by covering the heat radiating means with the metal plate, it is possible to prevent accidental touching of the heat radiating means and burns.
[0035]
Further, the casing is provided with a lid that can be opened and closed, and the lid is opened to operate the input connection disconnection means. Thereby, even if it does not open a housing | casing, it is easy to isolate | separate a pressure | voltage rise means and a solar cell or an inverter only by opening a cover part, Therefore The safety | security of the whole system can be improved.
[0037]
DETAILED DESCRIPTION OF THE INVENTION
FIG. 1 is a diagram showing an example of a photovoltaic power generation system including a boosting unit and an inverter device according to an embodiment of the present invention. In FIG. 1, only two solar cell strings 2a and 2b are shown for simplification of the drawing, but usually more solar cell strings are included.
[0038]
A standard solar cell string 2 a and a non-standard solar cell string 2 b are connected to the boost unit 1, and each output power is input to the boost unit 1. The step-up unit 1 is further connected to an inverter 4, and the inverter 4 converts the DC power output from the step-up unit 1 into AC power having the same phase and frequency 50/60 Hz as the commercial power system 5. 5 is supplied.
[0039]
The step-up unit 1 includes a step-up device 3, a control circuit 15, a trip signal generator 28, backflow prevention diodes 6a and 6b, lightning surge absorbers 7a and 7b, and input breakers 8a and 8b.
[0040]
The backflow prevention diodes 6a and 6b prevent a direct current from flowing back from the boost unit 1 side to the solar cell strings 2a and 2b side. The lightning surge absorbers 7a and 7b prevent lightning surges from entering the boosting unit 1 side from the solar cell strings 2a and 2b side. The input breakers 8a and 8b connect or disconnect the solar cell strings 2a and 2b and the boosting unit 1 side.
[0041]
Booster 3 includes a reactor 9, a switching element 10, a diode 11, a capacitor 13, a fuse 12, and a temperature sensor 14. Reactor 9 stores and releases the energy of DC power input to booster unit 1. The switching element 10 performs on / off switching by a high-frequency control output from the control circuit 15. Capacitor 13 stores the energy released by reactor 9 when switching element 10 is turned off. The fuse 12 opens the circuit when a current exceeding a certain set value flows. The temperature sensor 14 monitors the temperature of the switching element 10 and supplies the output to the trip signal generator 28. The trip signal generator 28 is supplied with the output voltage Vout of the step-up unit 1 and the temperature signal Ts of the temperature sensor 11, and the trip signal generator 28 receives an input breaker when the output voltage Vout becomes larger than a predetermined voltage. A trip signal Tp for tripping 8a and 8b is output.
[0042]
FIG. 2 is a specific block diagram of the control circuit 15 shown in FIG. 2, the control circuit 15 includes an initial boost ratio setting unit 16, an actual boost ratio setting unit 17, a boost ratio comparison unit 18, a signal setting calculation unit 19, a triangular wave generation unit 20, a signal comparison unit 21, a voltage comparison unit 22, and a signal. The setting calculation unit 23, the triangular wave generation unit 24, the signal comparison unit 25, the logical product calculation unit 26, and the gate drive unit 27 are included.
[0043]
The initial boost ratio setting unit 16 is a ratio between the number n1 of solar cell modules included in the standard solar cell string 2a and the number n2 of solar cell modules included in the non-standard solar cell string 2b, that is, the boost ratio α1 (= n1 / n2). Set. The actual boost ratio setting unit 17 sets the actual boost ratio α2 (= Vout1 / Vin) from the input voltage Vin and output voltage Vout1 of the boost unit 1 for each sampling.
[0044]
The initial boost ratio α1 obtained from the initial boost ratio setting unit 16 and the actual boost ratio α2 obtained from the actual boost ratio setting unit 17 are compared with each other by the boost ratio comparison unit 18, and the error is amplified and the signal setting calculation unit 19 is amplified. Is output.
[0045]
3 and 4 are waveform diagrams in the booster unit control circuit according to the embodiment of the present invention. As shown in FIG. 3A, the signal comparison unit 21 compares the signal setting value Ma obtained by the signal setting calculation unit 19 and the triangular wave Ta having an amplitude value of 0 to 1 generated by the triangular wave generation unit 20. When the signal set value Ma is larger than the triangular wave Ta, the signal comparison unit 21 performs PWM control for outputting the gate OFF level. As a result, the signal comparison unit 21 outputs the pulse signal PSa.
[0046]
Further, the preset voltage Vref1 and the output voltage Vout1 of the boosting unit 1 are input and compared by the voltage comparison unit 22 for each sampling. Then, the result is output to the signal setting calculation unit 23. Further, as shown in FIG. 3B, the signal setting value Mb obtained by the signal setting calculating unit 23 and the triangular wave Tb having an amplitude value of 0 to 1 generated by the triangular wave generating unit 24 are the signal comparing unit 25. When the signal set value Mb is larger than the triangular wave Tb, the signal comparison unit 25 performs PWM control for outputting the gate OFF level.
[0047]
As a result, the signal comparison unit 25 outputs the pulse signal PSb. These pulse signals PSa and PSb are input to the AND operation unit 26, and an AND operation is performed. As a result, a pulse signal PSc is generated as shown in FIG. The pulse signal PSc is input to the gate drive unit 27 for the switching element 10.
[0048]
Next, the operation of the booster unit 1 configured as described above will be described. As described above, the boost unit 1 is based on the boost ratio α (= n1 / n2) determined from the number n1 of solar cell modules of the standard solar cell string 2a and the number n2 of solar cell modules of the nonstandard solar cell string 2b. The input voltage is boosted and the output voltage is supplied to the inverter 4. When the output voltage of the boost unit 1 is within the input voltage range of the inverter 4, the boost unit 1 performs a boost ratio constant control to keep the boost ratio constant. That is, the control circuit 15 performs an AND operation on the signal set value Ma obtained from the initial boost ratio α1 and the actual boost ratio α2 and the pulse signal PSa (FIG. 3B) that outputs the gate OFF level from the triangular wave Ta. Output to.
[0049]
At this time, since the output voltage Vout1 of the boosting unit 1 is within the input voltage range Vref1 of the inverter 4 (Vout1 <Vref1), the voltage comparison unit 22 sets the signal setting value Mb of the output amplitude value 0 of the signal setting calculation unit 23 to The signal is input to the signal comparison unit 25. Then, PWM control based on the triangular wave Tb signal set value Mb is performed by the signal comparison unit 25, and a pulse signal PSb having a pulse width of 1 as shown in FIG. . Since the pulse signal PSb has a pulse width of 1, as shown in FIG. 4B, a pulse signal PSc similar to the pulse signal PSa is output to the gate drive unit 27 as a result of the AND operation. At this time, the control target is a constant step-up ratio.
[0050]
On the other hand, when the inverter 4 connected to the output side of the boosting unit 1 is not in operation, the boosting unit 1 is in a no-load state. Therefore, when the boosting unit 1 performs the boosting operation, the output voltage of the boosting unit 1 Exceeds the input voltage range of the inverter 4. Therefore, when the output voltage of the boosting unit 1 exceeds the input voltage range of the inverter 4, the boosting unit 1 changes the boosting ratio α to be small, and the output voltage of the boosting unit 1 is within the input voltage range of the inverter 4. Constant voltage control is performed so that
[0051]
That is, as described above, since the output voltage Vout1 of the boosting unit 1 is equal to or higher than the input voltage range Vref1 of the inverter 4 (Vout1> Vref1) at this time, the voltage comparison unit 22 is shown in FIG. As shown in the figure, first, the signal setting calculation unit 23 is caused to input a signal setting value Mb having an amplitude value of 1 or less and a value larger than 0 (for example, 0.1) to the signal comparison unit 25. The signal comparison unit 25 compares the triangular wave Tb with the signal set value Mb to perform PWM control, and the pulse signal PSb shown in FIG. 4D is output to the AND operation unit 26.
[0052]
At this time, if the pulse width of the pulse signal PSb is larger than the pulse signal PSa, a pulse signal PSc similar to the pulse signal PSa is output to the gate drive unit 27 as a result of the logical product operation. In this state, since the output voltage Vout1 of the boosting unit 1 is not less than the input voltage range Vref1 of the inverter 4 (Vout1> Vref1), the voltage comparison unit 22 sends a signal having a value larger than the previous amplitude value to the signal setting calculation unit 23. The set value Mb is input to the signal comparison unit 25. Then, the signal comparison unit 25 compares the triangular wave Tb with the signal set value Mb, and PWM control is performed. In this way, the pulse signal PSb is input from the signal comparison unit 25 to the logical product operation unit 26.
[0053]
As a result, when the pulse signal PSb having the pulse width as shown in FIG. 4B is input to the AND operation unit 26 and the pulse width of the pulse signal PSb is smaller than the pulse signal PSa, the pulse signal PSb shown in FIG. As shown, the AND operation unit 26 outputs a pulse signal PSc similar to the pulse signal PSb to the gate drive unit 27. As a result, the control is switched from the constant boost ratio control to the control in which the boost ratio α changes small, that is, the constant voltage control in which the output voltage of the boost unit 1 is within the input voltage range of the inverter 4. At this time, the control target is a constant output voltage.
[0054]
Furthermore, even if the boost unit 1 performs constant voltage control, that is, even if the boost ratio α is reduced, the output voltage becomes equal to or higher than the input voltage range of the inverter 4, and the boost ratio α cannot be further reduced. When overvoltage occurs, the input breaker 8b is tripped and the line with the solar cell string 2b side is opened. That is, as shown in FIG. 1, the trip signal generator 28 monitors the output voltage Vout2, and the output voltage Vout2 becomes larger than the preset input voltage range Vref2 (Vref1 <Vref2) of the inverter 4. (Vout2> Vref2), a trip signal Tp is sent from the trip signal generator 28 to the input breaker 8b, the input breaker 8b trips and the line to the solar cell string 2b side is opened.
[0055]
Further, when the switching element 10 is short-circuited, a short-circuit current flows between the solar cell string 2 b side and the switching element 10. When the short circuit current flows, the temperature of the switching element 10 rises. If the short-circuit current continues to flow, the temperature rise of the switching element 10 increases, which may lead to failure of the booster unit 1. Therefore, the trip signal generator 28 monitors the temperature Ts of the switching element 10 via the temperature sensor 29 attached to the switching element 10, and if the temperature exceeds the set temperature, the trip signal generator 28 detects the input breaker trip signal Tp. To trip the input breaker 8b and open the line to the solar cell string 2b side. By doing in this way, it is possible to interrupt the short-circuit current without continuously flowing it.
[0056]
Further, when a short-circuit current flows between the output side of the boosting unit 1, that is, the inverter 4, the switching element 11 or the like may break down. Therefore, it is possible to prevent the short circuit current from continuously flowing due to the fuse 12 provided before the capacitor 13 in the booster 3 being blown.
[0057]
As the switching element 10 of the boosting unit 1 shown in FIG. 1, for example, a field effect transistor (FET) or an insulated-gate bipolar transistor (IGBT) can be used. Further, the control circuit 15 may be composed of an analog circuit or a digital circuit.
[0058]
5A and 5B are external views of a casing in which the boosting unit according to the embodiment of the present invention is housed. In particular, FIG. 5A shows a front view, FIG. 5B shows a side view, and FIG. 5C shows a bottom view. Indicates. 6 is a view showing the internal structure of the housing shown in FIG. 5, wherein (a) is a front view with the cover of FIG. 5 removed, and (b) is a bottom view. FIG. 7 shows the structure of the lid member shown in FIG. 5, (a) is a front view of the lid, and (b) is a cross-sectional view showing an attached state of the lid.
[0059]
The housing 30 shown in FIG. 5 accommodates the booster unit 1 shown in FIG. 1 and is vertically installed along the outdoor wall surface 40 as shown in FIG. The housing 30 is composed of a main body 31 and a cover 32 covering the main body 31, and inside the main body 31, as shown in FIG. 6A, a barrier portion 33 serving as a drainage path along the upper surface and side surfaces. Is formed. The barrier unit 33 guides rainwater soaked between the main body 31 and the cover 32 to the lower part of the main body 31 and discharges it to the outside through a drain hole 34 as a discharge port formed in the lower part of the main body 31. . As a result, it is possible to prevent rainwater from being applied to the boosting device 3 and the conductive portion of the control circuit 15 housed in the housing 30 installed outdoors.
[0060]
A heat radiating fin 35 is attached to the lower portion (right side in FIG. 5B) of the main body 31 of the housing 30. The reverse fins 6a and 6b and the switching element 10 in the booster 3 shown in FIG. 1 are attached to the radiating fin 35, and the reverse flow preventive diodes 6a and 6b and the switching element 10 in the booster 3 are generated due to loss. Heat can be released to the outside, and the heat dissipation effect can be improved.
[0061]
Furthermore, a U-shaped metal plate 41 is provided so as to surround the radiation fin 35. A hook 42 for holding the main body 31 is formed inside the metal plate 41. Then, the metal plate 41 is attached to the wall surface 40, and the housing 30 is attached along the wall surface 40 in the vertical direction by holding the main body 31 by the hook 42. Further, the metal plate 41 is formed so as to cover the radiating fin 35, and the backflow preventing diodes 6 a and 6 b and the switching element 10 are heated to the radiating fin 35 whose temperature has been increased by heat generated by the loss while the booster 3 is operating. You can prevent burns even if touched accidentally.
[0062]
A display unit 36 is provided at the center of the cover 32 of the housing 30. The display unit 36 is turned on when the booster 3 is started and turned off when the booster 3 is stopped. Thereby, it can be confirmed whether the booster unit 1 is operating during the daytime when the solar radiation intensity is strong, without opening the main body of the booster unit 1. For example, if it is turned off during the daytime, the booster 3 is not operating. Therefore, it can be confirmed by the display unit 36 whether or not the boosting unit 1 is normal.
[0063]
Further, a cover 37 is provided at the bottom of the cover 32 so as to cover the opening. When the lid portion 37 is removed from the main body 31, as shown in FIG. 6A, the operation of the input breakers 8a and 8b attached inside the main body 31 is allowed. As shown in FIG. 7A, an attachment rail portion 38 is formed on one side of the lid portion 37, and a fastener 39 is attached to the other side. Further, a waterproof member 45 such as rubber is attached to the contact portion between the lid portion 37 and the main body 32.
[0064]
The fastener 39 has a fixing plate 391 and a knob portion 392. When the knob portion 392 is turned, the fixing plate 391 is rotated, and the lid portion 37 is removed from or attached to the booster unit 1 body by the operation. Can do. When the lid 37 is opened, the input breakers 8a and 8b can be operated, and the input breakers 8a and 8b can be operated from the outside simply by opening the lid 37 without opening the main body of the booster unit 1. can do. Furthermore, since no screw or the like is used for the lid portion 37, the lid portion 37 can be easily removed without using a special tool when removing the lid portion 37 from the housing 30. Therefore, the boosting unit 1 and the solar cell 2 or the inverter 4 can be easily disconnected in an emergency, so that the safety of the entire system can be improved.
[0065]
As described above, according to this embodiment, with respect to the connection between the DC power source such as the solar cell strings 2a and 2b, the boosting unit 1 and the inverter 4, the installation space dedicated for connection is reduced inside and outside the building, and the dedicated The housing 30 is integrated so as to reduce the cost of the entire apparatus, the wiring for connecting is reduced so that the indoor and outdoor scenery is not damaged, and the inverter 4 is overvoltaged during the operation of the booster unit 1. In addition, even if the switching element 10 fails or is short-circuited, a safe device that does not continue to generate a short-circuit current can be realized.
[0066]
The embodiment disclosed this time should be considered as illustrative in all points and not restrictive. The scope of the present invention is defined by the terms of the claims, rather than the description above, and is intended to include any modifications within the scope and meaning equivalent to the terms of the claims.
[0067]
【The invention's effect】
  As described above, according to the present invention, a booster unit that boosts and converts a voltage of a DC power source such as a solar cell by an opening / closing operation of a switching circuit and supplies the boosted DC voltage to AC power is supplied to an inverter device.Boosting means for boosting the voltage of a DC power supplyAnd an input connection function that directly connects the DC power supplyThe boosting means performs constant boost ratio control that keeps the boost ratio constant when the output voltage of the boost unit is lower than the set voltage, and outputs the boost unit when the output voltage of the boost unit is higher than the set voltage. Constant voltage control is performed by changing the step-up ratio so that the voltage is a constant voltage lower than the set voltage.As a result, it is possible to reduce the dedicated space for installation inside and outside the building. Moreover, since the booster unit is directly connected to the inverter without a connection box, the indoor landscape is not impaired.
  In addition, when the output voltage of the booster unit is lower than the set voltage, the booster ratio is controlled so that it is a nonstandard solar cell string when the booster is operating during the daytime when the solar radiation is strong. However, DC power similar to that of a standard solar cell string can be supplied to the inverter device. Therefore, it is possible to effectively use a limited space such as a roof of a building.
  Further, when the output voltage of the boost unit is higher than the set voltage, constant voltage control is performed by changing the boost ratio, so that the output voltage can be prevented from exceeding the set value. Therefore, overvoltage can be applied to the inverter device and failure can be prevented, and safety can be improved.
[0068]
  Also, RisingBackflow prevention means for preventing current from flowing back from the pressure means side to the DC power supply side;,straightBy providing lightning surge prevention means to prevent lightning surge from entering the boosting means side from the flow power supply,meansIn addition, current does not flow backward from the inverter device side to the solar cell side, and the solar cell side and the boosting means side, and the boosting device side and the inverter device side can be safely connected or disconnected during construction or the like.Further, it is possible to prevent lightning surges from entering the boosting means side and the inverter device side from the solar cell side during a lightning strike, thereby ensuring the safety of the inverter device.
[0073]
  Furthermore, the trip signal generating meansOf boosting meansA trip signal is generated in response to the output voltage becoming overvoltage,Input connection disconnectionWhen the boosting unit is operating in the daytime when the solar radiation intensity is increased by opening the connection to the DC power source by means, the boosting means can be used even if the boost ratio constant control or constant voltage control is performed.ofOutput voltageButWhen it is detected that an overvoltage has occurred, the trip signal generating means performs a trip operation to open the circuit, so that an overvoltage is applied to the inverter device and a failure can be prevented.
[0074]
The trip function in the input connection disconnecting means opens the path through which the short-circuit current flows according to the temperature rise of the boosting means, so that the boosting means is short-circuited when the boosting unit is operating in the daytime when the solar radiation is strong. When the short-circuit current flows between the solar cell and the booster, the temperature of the booster rises, so the temperature is monitored and the trip signal generator generates a trip signal and opens the circuit when the temperature rises above the set value. By doing so, it is possible to prevent the short-circuit current from continuously flowing, and to prevent the booster unit from being damaged by the short-circuit current.
[0077]
Also, at least the input connection section is housed in a case installed outdoors, and the case has a drainage path that guides the rainwater to the bottom when rainwater soaks, and a discharge port that discharges the rainwater led to the bottom to the outside. As a result, rainwater can be prevented from entering the conductive portions of the inverter device and the control circuit, and the cost of the entire device can be reduced by integrating a dedicated housing.
[0078]
  In addition, the outside of the housingunitBy providing a heat radiating means for radiating heat generated from the outside to the outside, the heat radiating effect can be enhanced.
[0079]
Furthermore, by including a metal plate for covering the heat dissipation means of the casing and supporting the casing on the wall surface, it is possible to eliminate the possibility of hand touching the heat dissipation means and causing burns. it can.
[0080]
In addition, the casing is provided with a lid that can be opened and closed, and by opening the lid and operating the input connection disconnection means, the boosting unit and the DC power source can be disconnected in an emergency.
[Brief description of the drawings]
FIG. 1 is a block diagram of a boosting unit according to an embodiment of the present invention.
FIG. 2 is a block diagram of a control circuit in the boosting unit shown in FIG.
FIG. 3 is a waveform diagram of each part of the control circuit.
FIG. 4 is a waveform diagram of each part of the control circuit.
FIG. 5 is an external view of a housing in which a booster unit according to an embodiment of the present invention is housed.
6 is a diagram showing an internal structure of the housing shown in FIG.
7 is a diagram showing a configuration of a lid portion of the housing shown in FIG. 5. FIG.
FIG. 8 is a block diagram of a conventional boost unit.
9 is a block diagram of the control circuit shown in FIG. 8. FIG.
10 is a waveform diagram of each part of the control circuit shown in FIG. 9;
[Explanation of symbols]
1 Boosting Unit, 2a Standard Solar Cell String, 2b Non-Standard Solar Cell String, 3 Booster Device, 4 Inverter Device, 5 Commercial Power System, 6a, 6b Backflow Prevention Diode, 7a, 7b Lightning Surge Absorber, 8a, 8b Input Breaker, 9 Reactor, 10 switching element, 11 diode, 12 fuse, 13 capacitor, 14 temperature sensor, 15 control circuit, 16 initial boost ratio setting unit, 17 actual boost ratio setting unit, 18 boost ratio comparison unit, 19, 23 signal setting calculation unit , 20, 24 Triangular wave generation unit, 21, 25 Signal comparison unit, 22 Voltage comparison unit, 26 AND operation unit, 27 Gate drive, 28 Trip signal generation unit, 30 Housing, 31 Body unit, 32 Cover, 33 Barrier unit , 34 Drain hole, 35 Radiation fin, 36 Display part, 37 Cover part 38 Rail part, 39 Fastener, 391 Fixing plate, 392 Knob part, 45 Waterproofing member.

Claims (10)

A step-up unit for boosting and converting a voltage of a DC power source such as a solar cell by an opening / closing operation of a switching circuit and supplying the boosted DC voltage to AC power,
Boosting means for boosting the voltage of the DC power supply;
An input connection function unit for directly connecting the DC power supply and the booster ;
The boosting means performs a boost ratio constant control to keep the boost ratio constant when the output voltage of the boost unit is lower than a set voltage, and when the output voltage of the boost unit is higher than the set voltage, A step-up unit that performs constant voltage control by changing the step-up ratio so that an output voltage of the step-up unit becomes a constant voltage lower than the set voltage . The input connection function unit
Backflow prevention means for preventing current from flowing back from the boosting means side to the DC power supply side ;
The boosting unit according to claim 1, further comprising: a lightning surge prevention means for preventing a lightning surge from entering from the DC power source to the boosting means side. The input connection function unit
Trip signal generating means for generating a trip signal in response to the output voltage of the boosting unit becoming an overvoltage;
Said DC power supply and connected to said boosting means, characterized in that it comprises an input connection disconnecting means for disconnecting said DC power source in response to said booster means to said trip signal, according to claim 1 or claim 2. The boosting unit according to 2. It said trip signal generating means further, in response to the boosting means has caused a short-circuit failure, characterized Rukoto forming issued the trip signal, boosting unit according to claim 3. It said trip signal generating means is characterized Rukoto issuing validate that the boosting means has caused a short-circuit failure on the basis of the temperature rise of the boosting means, boosting unit according to claim 4. Said trip signal generating means is characterized by generating the trip signal in response to the output voltage of the boosting unit exceeds a pre-determined input voltage range of the inverter device, the claims 3 to 5 The boosting unit according to any one of the above. Further, at least the input connection function unit is accommodated, and a housing for installing outdoors is provided .
Wherein the housing is characterized in that it comprises a drainage path for guiding the rain water at the bottom when soaked rain water, and a discharge port for releasing the rainwater that led to lower the outside, from the claims 1 to 6 The boosting unit according to any one of the above. Furthermore, the provided on the outside of the housing, characterized by comprising a heat dissipating means for dissipating heat generated from the booster unit to the outside, the boosting unit according to claim 7. Furthermore, before covering the Kiho heat means and characterized in that said housing comprises a metal plate for supporting the wall surface, the boosting unit according to claim 8. The housing has an openable lid portion, wherein said input connection disconnection means opens the lid portion is operated, the booster according to any one of claims 7 to claim 9 unit.

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